Dependence of the recoherence times and recoherence increments on the state of phonon bath in a single qubit dephasing model

The recoherence times $t^*$ and the maximum values of the recoherence increments $γ_{\rm extr}$ are studied as functions of the bath parameters for a single qubit dephasing model, prepared initially by a special kind of the non-selective measurements. The recoherence/decoherence events (RDE), occurring at the initial stage of the system evolution, are found to be both similar and different from the system dynamics at large times. For instance, in contrast to the RDE observed on large time scales, the sub-Ohmic and Ohmic coupling regimes are more favourable for the short-time recoherence than the super-Ohmic one. On the other hand, the short-time behaviour of the recoherence and the long-time dynamics of the decoherence are closely related: the domain of the ohmicity indexes, where the decoherence changes its type (from the complete to incomplete one), is, simultaneously, that of the weakest recoherence. The obtained results give us some hints about the basic characteristics of the environment, which might provide the most optimal values of $t^*$ and $γ_{\rm extr}$ in some sense.